Seattle Genetics has what it needs for accelerated enfortumab filing

In its phase II readout of enfortumab vedotin in advanced urothelial cancer Seattle Genetics got what the sellside called a “best-case scenario”: remission data that looked as good as phase I and that should support an accelerated US FDA submission. In the study, EV-201, subjects with urothelial cancer who progressed on a chemotherapy-checkpoint inhibitor combination had a 44% objective response rate. The result is especially impressive since the phase I trial hit 41% in patients whose tumours expressed nectin-4, the target of enfortumab, while phase II was in all-comers. The group added that the durability of response was similar to that seen in phase I, roughly seven months. An accelerated FDA submission is expected this year, while a confirmatory phase III trial, with overall survival as an endpoint, has already been initiated. Enfortumab sales beginning in 2020 would be welcome, as Seattle is still reliant on its one marketed product, Adcetris. Whether enforumab will also be submitted for accelerated European approval is subject to discussions with the group’s partner, Astellas. As for moving to first-line treatment, Seattle said it was not sure what its strategy would be beyond using enfortumab as a backbone, because the standard of care is changing quickly.